1. Field of the Invention
The present invention relates to an optical disk apparatus ensuring effective use of the recording area of an optical disk, and to a method for controlling the optical disk apparatus.
2. Description of the Related Art
One of the typical standards of optical disks capable of recording/reading out information utilizing a laser beam is a CD (Compact Disk) standard for the data-recordable (Write Once) CD-R, the re-recordable (ReWritable) CD-RW etc. In recent years, the CD-R disks and the CD-RW disks have been increasingly used accompanied by lowering of their prices and they have prevailed widely.
For an optical disk (a CD-standard medium) conforming with the physical format of the standard of a CD capable of recording/reading out, a pre-groove (guiding groove) wobbles (is winding) along a waveform FM-modulated by absolute time information etc. An ATIP (Absolute Time In Pre-groove) address being the absolute time information can be acquired by demodulating the frequency of the wobbling from this pre-groove. The ATIP address is utilized as management information for managing the recording/reading out position of data on the CD-standard medium in an optical disk apparatus executing recording/reading out of data in conformity with the logical format of the CD standard.
By the way, the storage capacity of a CD-R or a CD-RW disk is around 650 M bytes or 700 M bytes for a standard one. In recent years, a need for a larger capacity has been raised to optical disk media for the use for recording video image etc. Therefore, the standard recording capacity of the CD-R or the CD-RW can not cope with such a need.
Thus, for the optical disk apparatuses, a mechanism has been proposed, in which an ATIP address obtained from an existing CD-standard medium such as a CD-R or a CD-RW is converted into an address for high-density recording. The high-density recording to the CD-standard medium is realized utilizing the address for high-density recording. See, for example, Japanese Patent Application Laid-open Publication. No. 2002-56617. The address for high-density recording is an address given to each of segments in the case where a recording area (hereinafter, referred to as “one (1) ATIP section”) corresponding to one (1) ordinary sector segmented by an ATIP address is logically segmented into a predetermined number (the multiplying factor of recording density) of segments.
Furthermore, for an optical disk apparatus equipped with the mechanism described above (hereinafter, referred to as “conventional optical apparatus”), in the case where high-density recording is carried out to the CD-standard medium, a technique has been proposed, in which the logical format of a DVD (Digital Versatile Disk) standard such as a DVD-R or a DVD-RW is utilized. In the logical format of the DVD standard, it is provided that error correction is executed using Reed Solomon Code. Therefore, a conventional optical disk apparatus is equipped with a mechanism for encoding (modulation) processing for constituting one (1) ECC (Error Correction Code) block corresponding to 16 sectors by adding the Reed Solomon Code to recorded data, and a mechanism for decoding (demodulation) processing for decoding the above-mentioned one (1) ECC block read out from the CD-standard medium.
As described above, in the case of a high-density recording mode, i.e., where a logical format of the DVD standard is employed for the CD-standard medium, recording/reading out in one (1) ECC block as a unit, which is a unit for executing the error correction is employed as a principle.
By the way, in a CD-standard medium, a PCA (Power Calibration Area) is set for executing recording and reading-out of a predetermined testing signal for adjusting the recording power of the laser output emitted from an optical head. The size of the area of the PCA is defined to be 100 sectors (100 ATIP sections).
Here, in the case where a testing signal is recorded in units of ECC block to a PCA on a recordable CD-R disk, the PCA is used up by around 12 accesses. Then, data can not be recorded any more to the CD-R disk after the PCA is used up even when there is an empty area in the program area available to a user.
As described above, a conventional optical disk apparatus causes a problem that the recording area having a predetermined size set on a CD-standard medium is used up by making accesses in units of ECC blocks in a high-density recording mode even when the number of accesses made is small and, therefore, the effective use of the disk can not be facilitated.